Agricultural combines are the machinery used to harvest a number of different types of crops. A conventional combine includes a header assembly which cuts and collects the crop material as the combine is driven through the field. A feeder assembly communicates with the header assembly and advances the crop material to a rotor assembly on the combine. The rotor assembly threshes or otherwise separates the desirable crop material from the chaff or waste material.
A typical axial rotor assembly is characterized by a cylindrical shaped drum which is powered by a drive mechanism. The rotor assembly receives the crop material in an axial fashion, separates the desirable material and discharges the waste material at a discharge end of the rotor assembly. A plurality of threshing elements are attached to the outer periphery of the cylindrical drum. The rotor assembly may be driven at variable speeds depending upon the threshing element arrangement and the type of crop to be harvested. The threshing elements located on the outer periphery of the drum may have rasp or tooth-like configurations which make contact with the crop material as the rotor assembly is driven.
A casing or cage having specially adapted screen sizes surround the rotating drum allowing the desirable crop material to pass therethrough while the undesirable crop material is discharged at the discharge end of the rotor assembly.
A number of prior art references disclose various threshing element combinations, each combination tending to improve the threshing action by the rotor assembly with respect to one or more crop materials.
One well-known rotor assembly for harvesting many different types of crops is known as the "standard" rotor which includes a plurality of helical threshing elements which extend a portion of the length of the rotor assembly and which communicate with a plurality of straight bars or members. The helical threshing elements perform the threshing and the straight bars are used primarily to convey the crop material to a discharge end of the rotor. U.S. Pat. No. 5,145,462 is one example of a prior art reference which illustrates this standard rotor.
Other well-known combinations are known in the art as "specialty" rotors and are embodied in a number of other U.S. patents. A specialty rotor may be generally defined as one which includes an irregular pattern of threshing elements, each unique arrangement serving to better thresh a particular type of crop material or achieve some special advantage. A few specific examples of specialty threshing arrangements are found in U.S. Pat. Nos. 5,192,246; 4,889,517; 5,413,531; 5,035,675; 5,125,871; 5,192,245; and 5,413,531.
Another group of prior art references can be characterized by those which strictly illustrate a helical/spiral arrangement comprising a plurality of end to end threshing elements arranged in groups of spirals or helical patterns which extend along the length of the rotor. Examples of these prior art references include U.S. Pat. Nos. 4,266,393 and 4,505,279; German Patent No. DS-1938082; and Russian Patent No. 598-587.
Although each of the foregoing references may be adequate for their intended purposes, none disclose the unique threshing element pattern or arrangement herein.